Makii gave me some tips:
Apparently, the scaling of gear is favorable, so old instances can drop things that are very good. Jewellery is best, but armour won't have essence slots. Nonetheless, it may be a step up from 115 essence armour, especially since the armour value (which gives mitigation) will be much higher.
Epic/Big Battle reward jewellery, especially the teals, are also very good. I saw item level 355.
The 3-man instances may be easier than the solo. Because of low mitigations, you'll take damage, so having a healer helps vs self-heals in solo. Even t2 is feasible despite current low stats, and t2 drops are good.